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Entry  Sun Nov 8 14:35:25 2009, Frank, Laser, RefCav, resonance frequencies 
    Reply  Mon Nov 9 02:19:45 2009, rana, Laser, RefCav, resonance frequencies 
       Reply  Mon Nov 9 18:49:15 2009, Frank, Laser, RefCav, resonance frequencies 
Message ID: 5     Entry time: Mon Nov 9 18:49:15 2009     In reply to: 4
Author: Frank 
Type: Laser 
Category: RefCav 
Subject: resonance frequencies 

Quote:

I don't know if its worth the trouble, but we do have a ~200 MHz AOM. Sam Waldman had us buy one of these for doing the OMC g-factor measurements.

 

 i think the problem is that we don't have the VCO for the FSS for 200MHz. so i think it"s easier to heat one of the cavities. the temperature required to match them should be only a couple of Kelvin difference. and by heating one of those cavities the frequency noise due to ambient temperature fluctuations might be uncorrelated as well.

i had a problem taking the data from one of the photodiodes over the weekend. We had a loose connection for the cavity1 transmitted light PD. i only checked on a scope and assumed that the (already) connected cable to the DAQ is OK as i saw some fluctuations while scanning. so i have no data from that long scan over the weekend. we repaired this today and also made the FSS for the first cavity work. now everything is working and i started a new measurement...

sweep frequency is 50uHz which is almost 3h for the full ramp from min to max

C:PSL-FSS_RMTEMP is used for the heating voltage set point (not the heater voltage!). calibration is [-273-(voltage*100)] (is still calibrated for temperature sensors)

  • cavity1 is on resonance if C:PSL-FSS_RCTRANSPD is ~1.8V
  • cavity2 is on resonance if C:PSL-PMC_TRANSPD is ~780mV

we will add the temp sensors on the cavity tank tomorrow...

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